It is proposed to study in depth the effect of a single electrically induced seizure upon and the time-course of the recovery of the oxidation-reduction ratios and phosphorylation states of the cerebral cortex of unanesthetized adult male rats. Animals will be killed at various time intervals following the onset of the seizure by the almost instantaneous removal and freezing of the brain with a rapid brain freeze device (a "freeze-blower"). Perchloric acid extracts of the frozen tissue will be made and analyzed for the multiple metabolites used to calculate the free cytoplasmic (NAD ion)/(NADH) ration, the free cytoplasmic (NADP ion)/(NADHP) ration, the free mitochondrial (NAD ion)/(NADH) ration, and phosphorylation state, the free magnesium concentration or the shift in intracellular pH. A similar time-course will be taken of the changes of arterial blood pH, pO2, and pCO2. Blood will be drawn from indwelling catheters placed under light anesthesia once the animal is awake. From the several time-courses obtained the metabolic sequences of events and the interrelationship of the various energy mediators can be studied in the post-ictal state. This will yield not only basic information about energy metabolism during the post-ictal period and the sequence of events involved in recovery but also basic knowledge of cerebral energy metabolism in general. In addition, work is in progress on the effects of status epilepticus in paralyzed, ventilated animals on the pathways of serine synthesis and catabolism.